The present invention relates to oscillators and, more particularly, to an integrated oscillator circuit comprising a directional phase changer element.
Since inductive elements can not be readily integrated many prior art integrated oscillator circuits are of the relaxation type in which an external capacitor is charged or discharged through a resistor. Other types of integrated oscillators utilize external frequency determining means such as a crystal for setting the frequency of oscillation. Both of the aforementioned oscillators generally are limited in the range of oscillation and are not suited to be tuned over a broad oscillation band.
Hence, a need exists for an integrated oscillator circuit in which the capacitive elements thereof that are utilized in conjunction with other elements to set the frequency of oscillation, can be integrated on chip with all other elements of the oscillator. Further, it is desirable to be able to control the operating frequency of the oscillator over a broad range.